Abstract
The purpose of plasma exchange in cases of rheumatoid arthritis, is based on the idea of removing circulating immune complexes, immuno globlins and antibodies. A large amount of human blood products is necessary for plasma exchange in order to remove whole components of plasma. Problems such as an insufficiency of human blood products, loss of useful components of plasma, occur rence of hepatitis and so on, may be induced. In attempt to solve these problems, we were performed Double-filtration plasma exchange in four cases of rheumatoid ar thritis. However, it is our impression that the method of selectively separating RA-related components in plasma, needs modification.